Three major aspects of gene expression is mammalian cells productively infected and in cells transformed by herpes simplex 1 and 2 (HSV-1 plus HSV-2) will be investigated; 1) Virus-induced changes in low molecular weight (1mw) RNAs: The HSV-induced shut-off of host 7S RNA and tRNAs, the synthesis of virus specified lmw RNAs, including tRNA, and the role of 1mw RNA changes in the regulation of HSV and host gene expression will be studied. 2) DNA-dependent RNA polymerases involved in the transcription of HSV DNA: All forms of RNA polymerase present in HSV infected cells will be identified, isolated, fully characterized and compared to those present in uninfected cells. The RNA polymerases responsible for transcribing the different classes of HSV genes will be elucidated, including host enzymes and viral-coded alterations of transcriptional components. 3) Primary transcription, processing, polyadenylation, and transport of HSV RNA: These studies include a) complete characterization of the HSV-specific transcripts found in the nuclei of infected and transformed cells: b) identification and characterization of the HSV primary gene transcripts and the number and location of promoters; c) determination of the basic mechanism of HSV transcription (symmetric vs. asymmetric) throughout the infectious cycle; and d) investigation of the molecular mechanism of selective processing and transport of viral mRNA.